Sensory integration and segmental control of posture during pregnancy.

BACKGROUND: Approximately 25% of pregnant people fall, yet the underlying mechanisms of this increased fall-risk remain unclear. Prior studies examining pregnancy and balance have utilized center of pressure analyses and reported mixed results. The purpose of this study was to examine sensory and segmental contributions to postural control throughout pregnancy using accelerometer-based measures of sway. METHODS: Thirty pregnant people (first trimester: n = 10, second trimester: n = 10, third trimester: n = 10) and 10 healthy, nonpregnant control people stood quietly for one minute in four conditions: eyes open on a firm surface, eyes closed on a firm surface, eyes open on a foam pad, and eyes closed on foam. Postural sway was quantified using the root mean square accelerations in the anterior-posterior and medial-lateral directions from an inertial sensor at the lumbar region. Sensory sway ratios, segmental coherence and co-phase, were calculated to assess sensory contributions and segmental control, respectively. FINDINGS: Pregnant people did not display greater sway compared to healthy, nonpregnant controls. There were no group differences in vestibular, visual, or somatosensory sway ratios, and no significant differences in balance control strategies between pregnant and nonpregnant participants across sensory conditions. INTERPRETATION: The small effects observed here contrast prior studies and suggest larger, definitive studies are needed to assess the effect of pregnancy on postural control. This study serves as a preliminary exploration of pregnant sensory and segmental postural control and highlights the need for future to hone the role of balance in fall risk during pregnancy.

Recovery of turning speed in patients after vestibular schwannoma resection.

BACKGROUND: Individuals after a vestibular schwannoma resection (VSR) experience significant vestibular symptoms that can be provoked with turning. Vestibular rehabilitation assists in recovery of function and symptom relief, however turning response is unknown. OBJECTIVE: Examine peak turning speed response to surgery and rehabilitation. METHODS: Eight participants with a vestibular schwannoma (PwVS) and five healthy controls (HC) participated in this study. Peak turning speed (PTS) was captured with inertial measurement units (IMU) at the head and/or trunk during turning tasks at a pre-operative, post-operative and post-treatment assessment. Vestibular rehabilitation was provided twice weekly for six weeks. Linear mixed models were used to assess change in PTS across time points. RESULTS: PwVS performed slower PTS than HC prior to surgery. PTS was significantly slower post-operatively compared to pre-operative during walking with head turns (B = -61.03, p = 0.004), two-minute walk test (B = -37.33, p = 0.015), 360° turn (B range from 50.05 to -57.4, p < 0.05) and complex turning course (CTC) at the trunk (B = -18.63, p = 0.009). Post-treatment PTS was significantly faster than pre-operative during CTC at the head (B = 18.46, p = 0.014) and trunk (B = 15.99, p = 0.023). CONCLUSION: PwVS may have turning deficits prior to surgical resection. PTS was significantly affected post-operatively, however improved with rehabilitation.

Acute and Longitudinal Effects of Sport-related Concussion on Reactive Balance.

Postural instability is a common observation after concussions, with balance assessments playing a crucial role in clinical evaluations. Widely used post-concussion balance tests focus primarily on static and dynamic balance, excluding the critical aspect of reactive balance. This study investigated the acute and longitudinal effects of concussion on reactive balance in collegiate athletes. The assessments were conducted at pre-season baseline and 4 post-concussion timepoints: acute, pre-return-to-play, post-return-to-play, and six months post-concussion. The instrumented-modified Push and Release test measured reactive balance. Longitudinal effects of concussions on time to stability and step latency metrics were investigated applying Generalized Estimating Equations. Acutely after concussion, athletes demonstrated impaired reactive balance, indicated by longer times to stability, in dual-task conditions ( p = 0.004). These acute impairments were transient and recovered over time. Exploratory analyses revealed that athletes who sustained their first lifetime concussion exhibited both acute ( p = 0.037) and longitudinal ( p = 0.004 at post-return-to-play) impairments in single- and dual-task compared to controls with no lifetime concussion. This comprehensive evaluation provides insights into the multifaceted nature of post-concussion impairments and emphasizes the importance of considering cognitive demand and history of concussions in assessing athletes' balance.

Generalization of In-Place Balance Perturbation Training in People With Parkinson Disease.

BACKGROUND AND PURPOSE: Reactive balance training improves reactive postural control in people with Parkinson disease (PwPD). However, the extent to which reactive balance training generalizes to a novel, unpracticed reactive balance task is unknown. This study aimed to determine whether reactive training stepping through support surface translations can be generalized to an unpracticed, instrumented tether-release task. METHODS: Twenty-five PwPD (70.52 years ± 7.15; Hoehn and Yahr range 1-3) completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Stepping was trained through a 2-week (6-session) intervention with repeated support surface translations. Performance on an untrained tether-release task (generalization task) was measured at 2 baseline assessments (B1 and B2, 2 weeks apart), immediately after the intervention (P1), and 2 months after training (P2). The tether-release task outcomes were the anterior-posterior margin of stability (MOS), step length, and step latency during backward and forward steps. RESULTS: After support surface translation practice, tether-release stepping performance improved in MOS, step length, and step latency for both backward and forward steps compared to baseline (P < 0.05). Improvements in MOS and step length during backward and forward steps in the tether-release task, respectively, were related to stepping changes in the practiced task. However, the improvements in the generalization task were not retained for 2 months. DISCUSSION AND CONCLUSIONS: These findings support short-term generalization from trained balance tasks to novel, untrained tasks. These findings contribute to our understanding of the effects and generalization of reactive step training in PwPD.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content available at http://links.lww.com/JNPT/A465).

Vestibular Decompensation Following COVID-19 Infection in a Person With Compensated Unilateral Vestibular Loss: A Rehabilitation Case Study.

BACKGROUND AND PURPOSE: Surgical removal of a vestibular schwannoma (vestibular schwannoma resection; VSR) results in a unilateral vestibular hypofunction with complaints of dizziness and imbalance. Although the anatomic lesion is permanent, recovery of balance and diminution of dizziness occurs through central neurophysiologic compensation. Compensation of the system is maintained through daily activity. Unfortunately, interruption of stimulus, such as decreased activities due to illness, can cause decompensation. Decompensation is described as the return of symptoms consistent with that experienced during the initial insult/injury (eg, dizziness, oscillopsia, balance difficulty). This case study describes a reoccurrence of vestibular dysfunction in a person with a history of VSR following hospitalization and protracted recovery from a COVID-19 infection. It further documents her recovery that may be a result of vestibular rehabilitation. CASE DESCRIPTION: A 49-year-old woman (M.W.) with a surgical history of VSR (10 years prior) and a medical history of significant COVID-19 infection, resulting in an intensive care unit stay and prolonged use of supplemental oxygen, presented to physical therapy with persistent dizziness and imbalance. The video head impulse test confirmed unilateral vestibular hypofunction. INTERVENTION: M.W. attended biweekly vestibular rehabilitation for 6 weeks and completed daily home exercises. OUTCOMES: At discharge, M.W. demonstrated improvements in patient-reported outcomes (Dizziness Handicap Inventory), functional testing (MiniBEST, 2-Minute Walk Test), and gaze stability measures (video head impulse testing, dynamic visual acuity). DISCUSSION: Vestibular decompensation preluded by a COVID-19 infection caused a significant decrease in functional mobility. Vestibular rehabilitation targeted at gaze and postural stability effectively reduced symptoms and facilitated recovery to M.W.'s pre-COVID-19 level of function. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A458 ).

Turning speed as a more responsive metric of age-related decline in mobility: A comparative study with gait speed.

BACKGROUND: Navigating your environment requires both straight-line gait as well as turning. Gait speed normative values are well established and utilized in determining a person's functional status, however, it has limitations. This study sought to examine whether turning speed declines with age and how it compared to gait speed age-related decline. METHODS: A secondary analysis was performed on 275 community dwelling adults between the ages of 18-88 that performed a timed walking test with an inertial measurement unit on their lumbar spine. Turning speed and walking speed were extracted for each participant. A series of mixed models were compared, and Akaike's Information Criterion was used to determine the best fit model between age and turning speed and age and gait speed. FINDINGS: Turning speed and gait speed normative values were reported for each age decade. A linear model with a random intercept of "Condition" was used to assess the relationship between age and turning speed. The results indicated a significant negative relationship between age and turning speed (B = -0.66, p < 0.001). A spline-fit model determined a significant negative relationship between age and gait speed after the age of 65 (B = -0.0097, p = 0.002). The effect of age on gait speed before age 65 was not significant. INTERPRETATION: Turning speed significantly declines with age in a linear fashion while gait speed begins to decline after age 65. Turning speed may be more responsive to age than gait speed. More research is needed to determine if the decline in turning speed with age is associated with a decline in function.

Use of a Home-Based, Commercial Exercise Platform to Remotely Monitor Aerobic Exercise Adherence and Intensity in People With Parkinson Disease.

OBJECTIVE: Physical therapists are well-positioned to prescribe exercise outside of a clinical setting to promote positive health behaviors in people with Parkinson disease (PD). Traditionally, a barrier to precise exercise prescription has been reliance on participant self-reported exercise adherence and intensity. Home-based, commercially available exercise platforms offer an opportunity to remotely monitor exercise behavior and facilitate adherence based on objective performance metrics. The primary aim of this project was to characterize the feasibility and processes of remote aerobic exercise data monitoring from a home-based, commercially available platform in individuals participating in the 12-month Cyclical Lower Extremity Exercise for PD II (CYCLE-II) randomized clinical trial. Secondary aims focused on using exercise behavior to classify the cohort into exercise archetypes and describing a shared decision-making process to facilitate exercise adherence. METHODS: Data from each exercise session were extracted, visualized, and filtered to ensure ride integrity. Weekly exercise frequency was used to determine exercise archetypes: Adherent (2-4 exercise sessions per week), Over-adherent (>4 exercise sessions per week), and Under-adherent (<2 exercise sessions per week). RESULTS: A total of 123 people with PD completed 22,000+ exercise sessions. Analysis of exercise frequency indicated that 79% of participants were adherent; 8% were over-adherent; and 13% were under-adherent. Three case reports illustrate how shared decision-making with the use of exercise performance data points guided exercise prescription. CONCLUSIONS: The number of exercise sessions and completeness of the data indicate that people with PD were able to utilize a commercial, home-based exercise platform to successfully engage in long-term aerobic exercise. Physical therapists can use objective data as a part of a shared decision-making process to facilitate exercise adherence. IMPACT: Commercially available exercise platforms offer a unique approach for physical therapists to monitor exercise behavior outside of a clinical setting. The methods used in this project can serve as a roadmap to utilizing data from consumer-based platforms.

Reconsidering Vestibular/Ocular Motor Screening Cutoff Scores for Concussion.

INTRODUCTION: Vestibular/Ocular Motor Screening (VOMS) is often part of a comprehensive evaluation to identify acute mild traumatic brain injury. Most of the reports describe the use of the VOMS in adolescents/young adults and not in older adults or military service members. The purpose of this study was to describe VOMS findings in healthy civilians and active duty military service members up to the age of 50 years. MATERIALS AND METHODS: Seventy-seven healthy civilians between 18 and 50 years of age (22 males, age 31.8 [9.0] years) participated across three sites in addition to 40 healthy active duty service members (25 males, age 27.5 [4.9] years) from one site. Demographics, Neurobehavioral Symptom Inventory scores, mean near point convergence (NPC) distance, and Total Symptom Change (TSS) scores from the VOMS were evaluated. RESULTS: For civilians, the group mean NPC distance was 4.98 (3.8) cm. For military service members, the group mean NPC distance was 6.17 (4.57) cm. For civilians, the mean TSS was 1.2 (2.3) with 53.2% reporting 0 TSS, 27.3% reporting one TSS, and 19.5% reporting two or more TSS. For military service members, the mean TSS was 0.20 (0.72) with 92.5% reporting 0 TSS, 0% reporting one TSS, and 7.5% reporting two or more TSS. Age did not correlate with the mean NPC distance and TSS in healthy civilians and active duty military service members. CONCLUSIONS: Reconsideration of the Military Acute Concussion Evaluation, Version 2 cutoff value for abnormal mean NPC distance may be warranted to improve diagnostic accuracy in both civilian and military adult populations. Similarly, re-evaluating criteria for interpreting the TSS results of the VOMS, specifically in civilians, may be warranted.

Quantifying Turning Tasks With Wearable Sensors: A Reliability Assessment.

OBJECTIVE: The aim of this study was to establish the test-retest reliability of metrics obtained from wearable inertial sensors that reflect turning performance during tasks designed to imitate various turns in daily activity. METHODS: Seventy-one adults who were healthy completed 3 turning tasks: a 1-minute walk along a 6-m walkway, a modified Illinois Agility Test (mIAT), and a complex turning course (CTC). Peak axial turning and rotational velocity (yaw angular velocity) were extracted from wearable inertial sensors on the head, trunk, and lumbar spine. Intraclass correlation coefficients (ICCs) were established to assess the test-retest reliability of average peak turning speed for each task. Lap time was collected for reliability analysis as well. RESULTS: Turning speed across all tasks demonstrated good to excellent reliability, with the highest reliability noted for the CTC (45-degree turns: ICC = 0.73-0.81; 90-degree turns: ICC = 0.71-0.83; and 135-degree turns: ICC = 0.72-0.80). The reliability of turning speed during 180-degree turns from the 1-minute walk was consistent across all body segments (ICC = 0.74-0.76). mIAT reliability ranged from fair to excellent (end turns: ICC = 0.52-0.72; mid turns: ICC = 0.50-0.56; and slalom turns: ICC = 0.66-0.84). The CTC average lap time demonstrated good test-retest reliability (ICC = 0.69), and the mIAT average lap time test-retest reliability was excellent (ICC = 0.91). CONCLUSION: Turning speed measured by inertial sensors is a reliable outcome across a variety of ecologically valid turning tasks that can be easily tested in a clinical environment. IMPACT: Turning performance is a reliable and important measure that should be included in clinical assessments and clinical trials.

Stability Changes in Fall-Prone Individuals With Parkinson Disease Following Reactive Step Training.

BACKGROUND AND PURPOSE: Poor reactive steps may lead to falls in people with Parkinson disease (PwPD). However, whether reactive steps can be improved in PwPD at risk for falls or whether step training reduces falls remains unclear. This study aimed to determine whether 2 weeks of reactive step training result in (1) immediate and retained improvements in stepping and (2) fewer prospective falls in PwPD at fall risk. METHODS: Twenty-five PwPD (70.52 years ± 7.15; Hoehn & Yahr range 1-3) at risk for falls completed a multiple baseline, open-label, uncontrolled pre-/postintervention study. Stepping performance was assessed at 2 baseline assessments (B1 and B2) followed by a 2-week, 6-session training protocol. Stepping was assessed immediately (P1) and 2 months after training (P2). Primary outcomes were anterior-posterior margin of stability (MOS), step length, and step latency during backward stepping. Fall frequency was measured for 2 months before and after training. RESULTS: MOS during backward steps was significantly larger (better) after training ( P < 0.001, d = 0.83), and improvements were retained for 2 months ( P = 0.04, d = 0.66). Step length was not statistically significant different after training ( P = 0.13, d = 0.46) or at follow-up ( P = 0.08, d = 0.62), although effect sizes were medium and large, respectively. Step latency improved after initial exposure ( P = 0.01, d = 0.60) but not following training ( P = 0.43, d = 0.35). Twelve participants experienced fewer falls after training than before (10 = no change, 5 = increase; P = 0.12). Greater improvements in MOS were related to fewer falls ( P = 0.04). DISCUSSION AND CONCLUSIONS: Two weeks of reactive step training resulted in immediate and retained improvements in some reactive stepping outcomes in PwPD at risk for falls and may reduce fall risk. Reactive step training may be a viable approach to reduce falls in PwPD.

Instrumented Static and Reactive Balance in Collegiate Athletes: Normative Values and Minimal Detectable Change.

CONTEXT: Wearable sensors are increasingly popular in concussion research because of their objective quantification of subtle balance deficits. However, normative data and minimum detectable change values are necessary to serve as a references for diagnostic use and tracking longitudinal recovery. OBJECTIVE: Identify normative values and minimal detectable change values for instrumented static and reactive balance tests, an instrumented static Mediolateral Root Mean Square (ML RMS) sway standing balance assessment, and the instrumented, modified Push & Release (I-mP&R), respectively. DESIGN: Cross-Sectional Study. SETTING: Clinical Setting. PATIENTS OR OTHER PARTICIPANTS: Normative static ML RMS sway and I-mP&R data were collected on 377 (n=184 females) healthy National Collegiate Athletic Association Division I athletes at the beginning of their competitive seasons. Test-retest data were collected in 36 healthy control athletes based on standard recovery timelines after concussion. RESULTS: Descriptive statistics, intraclass correlation coefficients (ICC), and minimal detectable change (MDC) values were calculated for primary outcomes of mediolateral (ML) root-mean-square (RMS) sway in a static double limb-stance standing on firm ground and a foam block, and time to stability and latency from the I-mP&R in single- and dual-task conditions. RESULTS: Normative outcomes across static ML RMS sway and I-mP&R were sensitive to sex and type of footwear. ML RMS sway demonstrated moderate reliability in the firm condition (ICC=0.73; MDC=2.7cm/s2), but poor reliability in the foam condition (ICC=0.43; MDC=11.1cm/s2). Single- and dual-task time to stability from the I-mP&R exhibited good reliability (ICC=0.84 and 0.80, respectfully; MDC=0.25s, 0.59s, respectfully). Latency from the I-mP&R had poor to moderate reliability (ICC=0.38, 0.55; MDC=107ms, 105ms). CONCLUSIONS: Sex-matched references should be used for instrumented static and reactive balance assessments. Footwear may explain variability in static ML RMS sway and time to stability of the I-mP&R. Moderate-to-good reliability suggest time to stability from the I-mP&R and ML RMS static sway on firm ground can be used for longitudinal assessments.

Relation Between Cognitive Assessment and Clinical Physical Performance Measures After Mild Traumatic Brain Injury.

OBJECTIVES: To investigate the relation between cognitive and motor performance in individuals with mild traumatic brain injury (mTBI) and examine differences in both cognitive and motor performance between adults after mTBI and healthy controls. DESIGN: Multi-center, cross-sectional study. SETTING: Three institutional sites (Courage Kenny Research Center, Minneapolis, MN, Oregon Health & Science University, Portland, OR, and University of Utah, Salt Lake City, UT). PARTICIPANTS: Data were collected from 110 participants (N=110), including those with mTBI and healthy controls, who completed cognitive and physical performance assessments. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Cognitive assessments involved the Automated Neuropsychological Assessment Metrics to evaluate domains of attention, memory, reaction time, processing speed, and executive function. Physical performance was evaluated through clinical performance assessments, such as the 1-min walk test, the modified Illinois Agility Test, the Functional Gait Assessment Tool, the High-Level Mobility Assessment Tool, a complex turning course, and a 4-Item Hybrid Assessment of Mobility for mTBI. Participants also completed additional trials of the 1-min walk test, modified Illinois Agility Test, and complex turning course with a simultaneous cognitive task. RESULTS: Individuals with mTBI performed worse on cognitive assessments, as well as several of the physical performance assessments compared with healthy controls. Complex tasks were more strongly related to cognitive assessments compared with simple walking tasks. CONCLUSIONS: Combining complex motor tasks with cognitive demands may better demonstrate functional performance in individuals recovering from mTBI. By understanding the relation between cognitive and physical performance in individuals recovering from mTBI, clinicians may be able to improve clinical care and assist in return to activity decision-making.

Cognitive Predictors of Responsiveness to Reactive Step Training in People with Parkinson's Disease at Fall-Risk.

Reactive stepping can be improved in people with Parkinson's Disease (PwPD). However, there is variability in the responsiveness to such training. This study examined if cognition could predict the responsiveness of PwPD to a two-week reactive step training intervention. 25 PwPD (70.52 years ± 7.15; Hoehn & Yahr range 1-3) at risk for falls completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Reactive stepping was trained through a two-week (six-session) intervention with repeated support surface translations. Stepping performance was measured at two baseline assessments (B1 and B2), immediately after the intervention (P1), and two months after training (P2). Primary stepping outcomes were anterior-posterior margin of stability (MOS), step length, and step latency during backward steps. The primary aim assessed whether global cognition (Scales for Outcomes in Parkinson's Disease-Cognition - SCOPA-COG, & Montreal Cognitive Assessment - MoCA) was related to two-month retention of improvements in reactive stepping after practice. The secondary aim explored whether specific cognitive domains predicted retained stepping improvements, including attention/working memory, executive function, language, memory, and visuospatial function. Greater baseline global cognition was related to better two-month retention of step length improvements (SCOPA-COG: p = 0.002, f2 = 0.31; MoCA: p = 0.002, f2 = 0.38). However, only SCOPA-COG retained statistical significance after p-value adjustment for multiple comparisons (p = 0.04). Optimal cut-point analysis revealed that a SCOPA-COG threshold of 31 or higher was optimal for identifying individuals likely to retain improvement. Specific cognitive domains did not predict changes in reactive stepping outcomes. Participants with greater baseline global cognition, particularly as measured by SCOPA-COG, demonstrated greater retention of improvements in reactive stepping. In this cohort, a SCOPA-COG threshold of 31 could predict individuals likely to benefit from the intervention. These findings highlight the potential of cognitive screening to identify people more or less likely to benefit from reactive balance training.

People with multiple sclerosis and unilateral peripheral vestibular loss demonstrate similar alterations in head and trunk turning kinematics compared to healthy controls.

BACKGROUND: Individuals with peripheral vestibulopathy are known to have difficulty with volitional head turns. This leads to differences in head and body turning kinematics, compared to those without vestibular dysfunction. Multiple sclerosis (MS), a neuro-inflammatory disease affecting the central nervous system, can cause vestibular dysfunction (dizziness, unsteadiness, gaze instability). However, head and trunk turning kinematics in people with MS (PwMS) have not been assessed. RESEARCH QUESTION: Will PwMS, demonstrate head and body kinematics alterations similar to individuals with a peripheral dysfunction compared to vestibular healthy individuals? METHODS: Eleven individuals with a recent vestibular schwannoma resection (VSR), fourteen PwMS, and 10 healthy control (HC) participants were fitted with head and trunk worn inertial measurement units (IMUs) and performed walking and turning tasks. Head and trunk peak turning speed and amplitude were extracted. Regression models controlling for gait speed were fit per outcome with post hoc corrections applied to significant models. RESULTS: Yaw plane head turn speed and amplitude were significantly less in the VSR group compared to HC. Pitch plane head turn amplitude was significantly smaller in PwMS compared to HC (p = 0.04), however pitch plane speed did not differ between the groups. There was no difference between PwMS and the VSR group in yaw or pitch plane speed and amplitude. Both PwMS and the VSR group turned significantly slower than HC during the 180d body turn as measured at the head and trunk (head speed model p = 0.009 and <0.001; trunk speed model p < 0.001 for both groups) however the MS and VSR groups did not differ from each other. SIGNIFICANCE: Turning kinematics while walking in PwMS are altered compared to HC and are similar to individuals with unilateral vestibular hypofunction. Centrally mediated vestibular dysfunction in PwMS may alter movement kinematics and should be considered during examination and treatment.

Autonomic dysfunction and exercise intolerance in concussion: a scoping review.

PURPOSE: Concussion commonly results in exercise intolerance, often limiting return to activities. Improved understanding of the underlying mechanisms of post-concussive exercise intolerance could help guide mechanism-directed rehabilitation approaches. Signs of altered cardiovascular autonomic regulation-a potential contributor to exercise intolerance-have been reported following concussion, although it is not clear how these findings inform underlying mechanisms of post-concussive symptoms. Systematic summarization and synthesis of prior work is needed to best understand current evidence, allowing identification of common themes and gaps requiring further study. The purpose of this review was to (1) summarize published data linking exercise intolerance to autonomic dysfunction, and (2) summarize key findings, highlighting opportunities for future investigation. METHODS: The protocol was developed a priori, and conducted in five stages; results were collated, summarized, and reported according to PRISMA guidelines. Studies including injuries classified as mild traumatic brain injury (mTBI)/concussion, regardless of mechanism of injury, were included. Studies were required to include both autonomic and exercise intolerance testing. Exclusion criteria included confounding central or peripheral nervous system dysfunction beyond those stemming from the concussion, animal model studies, and case reports. RESULTS: A total of 3116 publications were screened; 17 were included in the final review. CONCLUSION: There was wide variability in approach to autonomic/exercise tolerance testing, as well as inclusion criteria/testing timelines, which limited comparisons across studies. The reviewed studies support current clinical suspicion of autonomic dysfunction as an important component of exercise intolerance. However, the specific mechanisms of impairment and relationship to symptoms and recovery require additional investigation.

The minimal clinically important difference for gait speed in significant unilateral vestibular hypofunction after vestibular rehabilitation.

Gait speed is a valid measure of both physical function and vestibular health. Vestibular rehabilitation is useful to improve gait speed for patients with vestibular hypofunction, yet there is little data to indicate how changes in gait speed reflect changes in patient-reported health outcomes. We determined the minimal clinically important difference in the gait speed of patients with unilateral vestibular hypofunction, mostly due to deafferentation surgery, as anchored to the Dizziness Handicap Index and the Activities Balance Confidence scale, validated using regression analysis, change difference, receiver-operator characteristic curve, and average change methods. After six weeks of vestibular rehabilitation, a change in gait speed from 0.20 to 0.34 m/s with 95% confidence was required for the patients to perceive a significant reduction in perception of dizziness and improved balance confidence.

Volitional Head Movement Deficits and Alterations in Gait Speed Following Mild Traumatic Brain Injury.

OBJECTIVE: Unconstrained head motion is necessary to scan for visual cues during navigation, for minimizing threats, and to allow regulation of balance. Following mild traumatic brain injury (mTBI) people may experience alterations in head movement kinematics, which may be pronounced during gait tasks. Gait speed may also be impacted by the need to turn the head while walking in these individuals. The aim of this study was to examine head kinematics during dynamic gait tasks and the interaction between kinematics and gait speed in people with persistent symptoms after mTBI. SETTING: A clinical assessment laboratory. DESIGN: A cross-sectional, matched-cohort study. PARTICIPANTS: Forty-five individuals with a history of mTBI and 46 age-matched control individuals. MAIN MEASURES: All participants were tested at a single time point and completed the Functional Gait Assessment (FGA) while wearing a suite of body-mounted inertial measurement units (IMUs). Data collected from the IMUs were gait speed, and peak head rotation speed and amplitude in the yaw and pitch planes during the FGA-1, -3, and -4 tasks. RESULTS: Participants with mTBI demonstrated significantly slower head rotations in the yaw ( P = .0008) and pitch ( P = .002) planes. They also demonstrated significantly reduced amplitude of yaw plane head rotations ( P < .0001), but not pitch plane head rotations ( P = .84). Participants with mTBI had significantly slower gait speed during normal gait (FGA-1) ( P < .001) and experienced a significantly greater percent decrease in gait speed than healthy controls when walking with yaw plane head rotations (FGA-3) ( P = .02), but not pitch plane head rotations (FGA-4) ( P = .11). CONCLUSIONS: Participants with mTBI demonstrated smaller amplitudes and slower speeds of yaw plane head rotations and slower speeds of pitch plane head rotations during gait. Additionally, people with mTBI walked slower during normal gait and demonstrated a greater reduction in gait speed while walking with yaw plane head rotations compared with healthy controls.

Reactive postural responses predict risk for acute musculoskeletal injury in collegiate athletes.

Identifying risk factors for musculoskeletal injury is critical to maintain the health and safety of athletes. While current tests consider isolated assessments of function or subjective ratings, objective tests of reactive postural responses, especially when in cognitively demanding scenarios, may better identify risk of musculoskeletal injury than traditional tests alone. OBJECTIVES: Examine if objective assessments of reactive postural responses, quantified using wearable inertial measurement units, are associated with the risk for acute lower extremity musculoskeletal injuries in collegiate athletes. DESIGN: Prospective survival analysis. METHODS: 191 Division I National Collegiate Athletic Association athletes completed an instrumented version of a modified Push and Release (I-mP&R) test at the beginning of their competitive season. The I-mP&R was performed with eyes closed under single- and dual-task (concurrent cognitive task) conditions. Inertial measurement units recorded acceleration and angular velocity data that was used to calculate time-to-stability. Acute lower extremity musculoskeletal injuries were tracked from first team activity for six months. Cox proportional hazard models were used to determine if longer times to stability were associated with faster time to injury. RESULTS: Longer time-to-stability was associated with increased risk of injury; every 250 ms increase in dual-task median time-to-stability was associated with a 36% increased risk of acute, lower-extremity musculoskeletal injury. CONCLUSIONS: Tests of reactive balance, particularly under dual-task conditions, may be able to identify athletes most at risk of acute lower extremity musculoskeletal injury. Clinically-feasible, instrumented tests of reactive should be considered in assessments for prediction and mitigation of musculoskeletal injury in collegiate athletes.

A Hybrid Assessment of Clinical Mobility Test Items for Evaluating Individuals With Mild Traumatic Brain Injury.

BACKGROUND AND PURPOSE: The Functional Gait Assessment (FGA) and High Level Mobility Assessment Tool (HiMAT) are clinical batteries used to assess people with mild traumatic brain injury (mTBI). However, neither assessment was specifically developed for people with mTBI; the FGA was developed to evaluate vestibular deficits, and the HiMAT was developed for individuals with more severe TBI. To maximize the sensitivity and reduce the time burden of these assessments, the purpose of this study was to determine the combination of FGA and HiMAT items that best discriminates persons with persistent symptoms from mTBI from healthy controls. METHODS: Fifty-three symptomatic civilians with persistent symptoms from mTBI (21% male, aged 31 (9.5) years, 328 [267] days since concussion) and 57 healthy adults (28% male, aged 32 (9.6) years) participated across 3 sites. The FGA and HiMAT were evaluated sequentially as part of a larger study. To determine the best combination of items, a lasso-based generalized linear model (glm) was fit to all data. RESULTS: The area under the curve (AUC) for FGA and HiMAT total scores was 0.68 and 0.66, respectively. Lasso regression selected 4 items, including FGA Gait with Horizontal Head Turns and with Pivot Turn, and HiMAT Fast Forward and Backward Walk, and yielded an AUC (95% confidence interval) of 0.71 (0.61-0.79) using standard scoring. DISCUSSION AND CONCLUSIONS: The results provide initial evidence supporting a reduced, 4-Item Hybrid Assessment of Mobility for mTBI (HAM-4-mTBI) for monitoring individuals with mTBI. Future work should validate the HAM-4-mTBI and investigate its utility for tracking progression throughout rehabilitation.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A409 ).

Reactive balance assessments complement clinical baseline concussion assessments in collegiate athletes.

CONTEXT: Current clinical concussion evaluations assess balance deficits using static or dynamic balance tasks while largely ignoring reactive balance. Including a reactive balance assessment in current evaluations might provide a more comprehensive concussion evaluation. OBJECTIVE: The purpose of this study was to determine if redundancy exists within current clinical baseline assessments of concussion and whether reactive balance adds unique information to these evaluations. DESIGN: Cross Sectional Study. SETTING: Clinical Assessment. PATIENTS OR OTHER PARTICIPANTS: Two cohorts of data were collected at the beginning of the athletic season from healthy NCAA Division I athletes. Within the first cohort (n = 191), correlation analyses with clinical scores and inertial measurements were run between the ImPACT (Immediate Post-Concussion Assessment and Cognitive Tool), the BESS (Balance Error Scoring System), the modified Push and Release (mP&R), and instrumented mP&R (I-mP&R) to determine the strength of a relationship between these concussion tests. Within the second cohort (n = 88), correlation analyses were run between the BESS, the mP&R, Timed Tandem Gait, Walking with eyes closed, and clinical reaction time to determine the strength of the relationship between these concussion evaluation tests. MAIN OUTCOME MEASURES: ImPACT cognitive indices, BESS and mP&R clinical score and instrumented measures (BESS sway; I-mP&R time to stability, latency, and step length), TTG and Walking time to completion, and clinical reaction time. RESULTS: The strongest inter-instrument correlation value was r= 0.347, which was considered a weak correlation, between clinical reaction time and single task time to stability from the I-mP&R. The I-mP&R and mP&R clinical scores were weakly associated with the other assessments. CONCLUSION: The weak correlations between inter-assessment variables indicates that there is little redundancy within the current clinical evaluations. Furthermore, reactive balance represents a unique domain of function that may improve the comprehensiveness of clinical assessments.